Mixture distribution control



Aug. 5, 1958 M. J. KITTLER 2,346,202

MIXTURE DISTRIBUTION CONTROL Filed April 25, 1955 IO [0 IO 12 a C 7 w r 9 2 a a 4 32 7 34 Y 36 F|G.2. FIG.3. FIG.4.

38 INVENTOR.

MILTON J.K|TTLER FIG.5. M

ATTORNEYS The present invention relates to mixture distribution control for a two stage carburetor, and more particularly, to a mixture distribution control system effective with part throttle opening.

Modern internal combustion engines of the V-8 type are of very short compact construction and are equipped with quite large two stage, four barrel carburetors. This creates somewhat of a mixture distribution problem since the carburetor is so large with respect to the manifold that the primary stage is not symmetrical with respect to the branches of the manifold. Since the primary stage is in operation at speeds up to 70 or 80 miles per hour, the mixture distribution at such part throttle operating conditions may be adversely affected by the above mentioned lack of symmetry.

it is an object of the present invention to overcome this difiiculty by the provision of mixture distribution control means effective to provide for transfer of a part of the fuel mixture from the primary barrel to the secondary barrel of the two stage carburetor to improve distribution.

More specifically, it is an object of the present invention to provide part throttle mixture distribution control for a two stage carburetor comprising a passage extending between primary and secondary barrels having an intake port in the primary barrel in position to be downstream from the usual throttle plate when the throttle plate is fully closed, but to be uncovered and to be effectively transferred to an upstream position upon initial and partial opening movement of the primary throttle plate, the passage having an outlet or discharge port in the secondary barrel in a position which is always downstream from the throttle plate therein.

It is a further object of the present invention to provide in a two stage carburetor, means operable in response to partial opening of the throttle plate in the primary barrel to effect transfer of part of the fuel mixture from the primary to the secondary barrel thereof.

It is a further object of the present invention to provide distribution means operable in accordance with the position of the throttle plate in the primary barrel of a carburetor for transferring part of the fuel mixture therefrom to the related secondary barrel thereof.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings, wherein:

Figure l is a side elevational view partly in section, of a two stage carburetor.

Figure 2 is a fragmentary sectional view extending longitudinally of the primary barrel showing the intake port of the fuel mixture distribution passage.

Figures 3, 4 and 5 are views similar to Figure 2, showing variations in shape of the intake port.

The carburetor illustrated in Figure 1 comprises a primary barrel it) having a movable throttle plate 12 therein. Fuel nozzle mechanism indicated at 14 is located in the throat of a venturi 16 and the primary barrel is provided with a choke valve 18 of usual design.

The carburetor includes a secondary barrel 20 including fuel inlet means indicated generally at 22. The sec- 2 ondary barrel 20 is provided with a movable throttle plate 24.

In order to provide for introduction of a combustible mixture into the manifold through the secondary barrel of the carburetor at speeds below those at which the throttle plate of the secondary barrel opens, there is provided a passage 26 having an intake port 28 and anout-.

let or discharge port 30.

The intake port 28 is located in the primary barrel at a position just downstream from the movable edge of the throttle plate 12 when the throttle plate is in its fully closed position. Furthermore, the intake port 28 is in a position such that initial opening movement of the throttle plate 12 from its fully closed position causes the adjacent edge of the throttle plate to move across the port 28 and thus in effect, to transfer the intake port 28 to the upstream side of the throttle plate. With the parts in the position illustrated inFigure 1, where the primary throttle plate 12 is shown as fully closed, the mixture distribution passage 26 is not operating. When however, the throttle is partly opened 'to bring the intake port 28 of the passage to the upstream side of the throttle plate and thus to expose it to the higher pressure existing at the upstream side thereof, there is a substantial flow of fuelair mixture through the passage 26 into the secondary barrel of the carburetor from which it flows into" the manifold in a manner to provide more uniform and efficient distribution of combustible mixture.

The present invention provides an arrangement in which the secondary barrel or barrels of a carburetor are used in the nominally low speed range so that more efficient distribution of fuel is obtained. In modern engines a very large percentage of the total driving time is spent at the so-called low speed ranges. Accordingly,the present invention provides means for improving efficiency of the engines under conditions which in practice are those normally encountered. At the same time, the improvement in the relatively low speed operation does not interfere with the efiiciency of the carburetor for high speed operation when the throttle plate of the secondary barrel is moved to the open position. At this time pressure at opposite ends of the passage 26 approach equivalence 5 there are shown different embodiments of the present invention which differ solely in the shape of the intake ports, designated as 32, 34, 36 and 38. In-Figure 2, the intake ports 32 are shown as of generally circular shape and as three in number. It will be apparent that these intake ports may be the intakes to three parallel passages, or they may communicate through branches to a single pas sage having a single outlet port in the secondary barrel.

The intake port 34 of Figure 3 is transversely elongated so as to provide a maximum flow of mixture to the secondary barrel with a minimum of movement of the throttle plate 12.

The intake port 36 of Figure 4 is shown as of triangular cross-section so arranged as to provide for a gradual increase in the flow of mixture from the primary to the secondary barrel upon initial movement of the primary throttle plate 12.

The intake port 38 illustrated in Figure 5 is in the shape of a trapezoid and will result in initial quick opening of the passage 26 upon initial movement of the Patented Aug. 5, 1958 3 throttle plate 12 to produce substantial flow of mixture therethrough with a further increase upon further movement of the throttle plate.

It will be appreciated that the present invention relates only to transfer of mixture from primary to secondary barrels of a two stage carburetor and that accordingly, the description in the present case is not complicated by a full description of the remaining parts of the carburetor, which may be of conventional type. However, as is Well understood, two stage carburetors include means responsive in some way to speed effective to open the throttle of the second stage only when required or only in response to completion of full opening movement of the throttle in the primary stage. The mechanism for effecting movement of the throttle in the secondary stage forms no part of the present invention and may be of any type illustrated in the patented or commercial prior art.

The drawings and the foregoing specification constitute a description of the improved mixture distribution control system in such full, clear, concise and exact terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What I claim as my invention is:

l. A two stage carburetor having primary and secondary barrels, controllable throttle plates movable only sequentially from closed toward open position in said barrels, a mixture distribution passage interconnecting said barrels, said passage having an intake port located in said primary barrel approximately adjacent a movable edge of the throttle plate in said primary barrel and in position to be downstream from said throttle plate when said throttle plate is in fully closed position, and to be effectively transferred to the upstream side of said throttle plate by movement of the adjacent edge of said throttle plate thereacross during initial movement from fully closed toward open position, said passage having an outlet port in said secondary barrel at a point always downstream from the throttle plate in said secondary barrel.

2. A two stage carburetor having primary and secondary barrels, controllable throttle plates movable only sequentially from closed toward open position in said barrels, mixture distribution control means including the throttle plate in said primary barrel operable during initial opening movement of the throttle plate in said primary barrel and before substantial opening movement of the throttle in said secondary barrel to divert a part of the main fuel supply mixture from said primary to said secondary barrel.

3. A two stage carburetor having primary and secondary barrels, controllable throttle plates in said barrels, mixture distributing control means operable to transfer a portion of the combustible mixture from within the primary to the secondary barrel of the carburetor whenever said primary throttle plate is at least partly open and said secondary throttle plate is closed.

4. In a twostage carburetor of the type having a primary and secondary barrel, a primary throttle plate in said primary barrel, a secondary throttle plate in said secondary barrel, and means for effecting sequential opening movement of said primary and secondary throttle plates so that said secondary throttle plate starts to open only after substantial opening movement of said primary throttle plate, whereby said secondary throttle plate will remain closed throughout a substantial range of operation, the improvement which consists of a mixture distribution passage interconnecting said barrels, said passage having an intake port located in said primary barrel adjacent the movable edge of the primary throttle plate, downstream therefrom when said primary throttle plate is in substantially fully closed position and in position to be traversed by the said edge of said primary throttle plate on initial opening movement to be efiectively transferred upstream thereof, said passage having an outlet port in said secondary barrel downstream from 4 said secondary throttle plate when said secondary throttle plate is in closed position.

5. In a two-stage carburetor of the type having a primary and secondary barrel, a primary throttle plate in said primary barrel, a secondary throttle plate in said secondary barrel, and means for effecting sequential opening movement of said primary and secondary throttle plates so that said secondary throttle plate starts to open only after substantial opening movement of said primary throttle plate, whereby said secondary throttle plate will remain closed throughout a substantial range of operation, the improvement which consists of a mixture distribution passage interconnecting said barrels, said passage having an intake port located in said primary barrel adjacent the movable edge of the primary throttle plate, downstream therefrom when said primary throttle plate is in substantially fully closed position and in position to be traversed by the said edge of said primary throttle plate on initial opening movement to be effectively transferred upstream thereof, said passage having an outlet port in said secondary barrel downstream from said secondary throttle plate independent of the position of said secondary throttle plate.

6. In a two-stage carburetor of the type having a primary and secondary barrel, a primary throttle plate in said primary barrel, a secondary throttle plate in said secondary barrel, and means for effecting sequential opening movement of said primary and secondary throttle plates so that said secondary throttle plate starts to open only after substantial opening movement of said primary throttle plate, whereby said secondary throttle plate will remain closed throughout a substantial range of operation, the improvement which consists of an uninterrupted mixture distribution passage interconnecting said barrels, said passage having an intake port located in said primary barrel adjacent the movable edge of the primary throttle plate, downstream therefrom when said primary throttle plate is in substantially fully closed position and in posi tion to be traversed by the said edge of said primary throttle plate on initial opening movement to be effectively transferred upstream thereof, said passage having an outlet port in said secondary barrel downstream from said secondary throttle plate when said secondary throttle plate is in closed position.

7. In a two-stage carburetor of the type having a primary and secondary barrel, a primary throttle plate in said primary barrel, a secondary throttle plate in said secondary barrel, and means for effecting sequential opening movement of said primary and secondary throttle plates so that said secondary throttle plate starts to open only after substantial opening movement of said primary throttle plate, whereby said secondary throttle plate will remain closed throughout a substantial range of operation, the improvement which consists of a straight, uninterrupted mixture distribution passage interconnecting said barrels, said passage having an intake port located in said primary barrel adjacent the movable edge of the primary throttle plate, downstream therefrom when said primary throttle plate is in substantially fully closed position and in position to be traversed by the said edge of said primary throttle plate on initial opening movement to be effectively transferred upstream thereof, said passage having an outlet port in said secondary barrel downstream from said secondary throttle plate when said secondary throttle plate is in closed position.

References Cited in the file of this patent UNITED STATES PATENTS 

